Mechanical apparatus



Oct. 18, 1966 MASTERSQN 3,279,690

MECHANICAL APPARATUS Filed Oct. 8, 1964 4 Sheets-Sheet 1 INVENTOR. EARL E. MASTERSON ATTORNEY.

Oct. 18, 1966 E. E. MASTERSON MECHANICAL APPARATUS 4 Sheets-Sheet 2 Filed 001;. 8, 1964 IFIG. 2

R SON INVEN' EARL E. MAS

ATTORNEY- Oct. 18, 1966 E. MASTERSON MECHANICAL APPARATUS 4 Sheets-Sheet 5 Filed Oct. 8, 1964 INVENTOR. EARL E. MASTERSON BY al 2!- ATTORNEY:

Oct. 18, 1966 E. E. MASTERSON 3,279,690

' MECHANICAL APPARATUS v Filed 001:. 8, 1964 4 Sheets-Sheet 4 [FIG. 5

EARL E. MASTERSON 44 aY 222' J- A TORNEY.

United States Patent Office 3,279,690 Patented Qct. 1.8, 1:96?

3,279,690 MECHANICAL APPARATUS Earl E. Masterson, Newtonville, Mass., assignor to Honeywell Inc., Minneapolis, Minn., a corporation of Delaware a i Filed Oct. 8, 1964, Ser. No. 402,412

18 Claims (Cl."234115) The present invention relates in general to new and improved mechanical actuatorsand in particular to actuators which are capable of operating at high speeds.

For purposes of illustration, the 'invention'will be explained with reference-to a card'punch unit, although it will be understood that it has general application. A universalrequirement in the operation of a multi-punch highsceed punch unit is the rapid and synchronous operation of all the punches which are simultaneously actuated. Conventionally this is accomplished by applying reciprocating linear-motion from a common'rnotive'source to a plurality ofactuators, eachadapted to transmit the motion toa corresponding punch. Each actuator includes an interposer which is selectively positioned in alignment With'the punch When punching is desired. The key to reliable operation then residesin the ability to shift the interposers rapidly and synchronously from a power transmitting'position' to an inactive'position, or vice versa.

Heretofore'available high-speed punch equipment has been relatively complex and expensive. Generally, such equipment has movingpivots and other areas 'of wear which must be kept properly lubricated. The interposer is usually connected to a moving armature so that the total mass which must be moved is relatively large. This tends to limit the speed of operation.- Partly due to'its complexity, such equipment hasbeen subject to breakdowns under sustained periodsof'operation and has oftenproved difl'icult to maintain in proper operating condition for appreciable periods of time. 'Frequently, the card punch equipment is part of a larger data processing system which is similarly disabled when the aforesaid breakdowns occur. i

Accordingly it is the primary object of the present invention to provide a mechanical actuator which overcomes the foregoing disadvantages.

It is another object of the present invention to provide a mechanical actuator of low mass for applying motion -to a driven element which responds rapidly to selectively applied control signals. i

It is a further object of the present invention to provide a simple and economical card punch unit including fiat leaf-flexure means wherein 'WeaFIS minimized by the absence ofpivots and other points requiring lubrication and which is easy to maintain in proper operating condition for-extended periods of operation.

" Further objects of the present invention, together with the features and advantages thereof, will become apparent from thefollowing detailed-description, when read in conjunction with the accompanying drawings in which:

FIGURE l illustrates an exemplary arrangement of punches ina serial multi-punch unit; Y

FIGURE-2 illustrates the pertinent features of a preferred embodiment of the present invention; 4

"FIGURE 3 illustrates a detailof theapparatus of FIG- URE 2 as applied to a multi-punch unit;

FIGURE 4 illustrates afurther detail of the apparatus of FIGURE 2, as applied to a multi-punch unit; and

FIGURE 5 illustrates another embodiment of the present invention. a it e With reference now to the drawings, the invention will be explained with reference to a serial punch unit wherein, for example, 24 punches disposed in two colums of 12 punches each, are simultaneously actuated. The arrangement of the punches is illustrated in FIGURE 1. It will be understood that the medium which is to be perforated, e.g. a card, moves in conventional manner below the lower punch ends which have been-omitted in the drawing for the sake of simplicity. Successive pairs of punches 10-11, 10'11, 10"11" etc., are spaced a distance D from each other and are substantially identical. The punch 10 includes an upper portion 12 which terminates in a striking surface 13, as well as a lower portion 14 connected to the upper portion by a shank16. The width of the shank 16 is less than that of the upper and lower portions 12 and 14, Le. it is recessed to define a pair of steps 18 on opposite sides of the punch. 'The punch 11 is substantially identical to the punch 10, having a-striking surface 15 and a pair of steps 20, as shown.

FIGURE 2 illustrates the pertinent features of a preferred embodiment of the subject actuator, applicable reference numerals having been retained. A bail 22 which forms part of the actuator, is symmetrically positioned with respect to the pair of punches 10 and 11 and'includes a pair ofcontoured guide surfaces24 and 26 facing in opposite directions with respect to each other and in alignment with the punches 10 and 11 respectively. The bail 22 further includes an extension 28 which terminates in a stripper 30 that is symmetrically positioned with respect to the punches 10 and 11. The stripper 30 is adapted to engage the steps 18 and 20 of the punches 10 and 11 respectively. Extension 28 projects from lower end 28 of bail 22. End 28' is relieved as shown so as to clear the punches when the latter are' not driven by an interposer. Despite such relief, however, the reduced tip of end 28projects guidingly'along fiexure interposers 40, 42 substantially coterminous therewith. That is, surfaces 24, 26 of bail22 extend relatively coplanar and guidingly along virtually the entire length of associated flexures 40, 42 respectively to stiffen them.

A pair of limit guides 32 and 34 is seen to be symmetrically positioned relative to the bail 22. The guides include contoured surfaces 36 and 38, spaced from the surfaces 24 and 26 respectively by prescribed like separation gaps, said gaps being maintained by associated stopprojection portions 3GL, 30-R of head 30,'respectively, e.g. so as to clear the punches 10, 11. The actuator illustrated in FIGURE 2 further includes a pair of interposer flexures 40am 42 in the form of flat leaf springs made of a magnetic material and shown in flexibly conforming contact with the bail surface 24 and with the guide surface 38 respectively. The interposer 40is shown in'its rest position and is seen to be aligned with the punch 10. In this position it is capable of transmitting a force to the punch by virtue of the back-up action of the contoured bail surface 24 which prevents the flexure 40 from buckling. The interposer 42 is shown in the no-punch position, out of alignment with its corresponding punch 11.

In a multi-punch unit of the type illustrated in FIGURE 1, two sets of interposer fiexures are employed, each set being associated with one column of aligned punches, so that one flexure corresponds to each punch. Similarly, a set of limit guides is associated With-each set of flexures. FIGURE 3 illustrates the positional relationship of one set of limit guides and interposer flexures respectively. In the example under consideration which employs 12 pairs of punches, there will be understood to be 12 corresponding pairs of interposers, that is, 2 sets of 12 fiexures each, a few of the flexures 40, 40, 40" etc., being shown in FIGURE 3, where eachflexure is adapted to be positioned above the striking surface of a corresponding punch. A set of limit guides 34,- 34', 34", etc., is shown, posi-. ti-oned to define a space S between successive guides, eachpair of successive guides being adapted to contact a flexure. It will be understood'that another set of limit guides and flexures respectively, substantially identical to those shown in FIGURE 3 and symmetrically positioned relative thereto, is employed in a multi-punch unit in accordance with the preferred embodiment of the present invention.

FIGURE 4 illustrates the bail 22, as applied to a multipunch unit. In the example under consideration, the bail has thirteen spaced extensions 28, 28', 28", etc., which terminate in corresponding strippers 30, 30', 30", etc. respectively. The strippers are respectively adapted to be positioned in the spaces D between successive punch pairs, as shown in FIGURE 1.

A single pair of punches 10, 11 is illustrated in phantom outline in FIGURE 4, in position between the strippers 30 and 30. The flexure 40 is also shown in phantom outline, in contact with the striking surface 13 of the punch 10. It will be seen that the mutual spacing of the strippers 30 and 30' accommodates only the shank portions of the punches and 11. The steps 18 and 20 of the punches are thus adapted to be engaged from below by .the strippers.

Reverting now to the preferred embodiment of the invention shown in FIGURE 2, one pair of magnet poles are seen as disposed adjacent each one of the limit guides 32 and 34, one magnet corresponding to each flexure. The magnets are positioned in the spaces S defined between successive limit guides. A representative pair of magnets 44 and 46, having pole faces 48, 50 and S2, 54 respectively, is shown in position in FIGURE 2. The magnet pole faces are seen to be stationed behind the guide surfaces 38 and 36 respectively. The magnets 44 and 46 further include windings 45 and 47 respectively,

each winding including a pair of terminals adapted to re- FIGURES 2 and 4. The shaft 60, which is adapted to have rotary power applied thereto, is eccentrically afiixed to a bearing 62. The latter is rotatably disposed in a housing 64 by a race of ball bearings 66. An extension 68 protrudes from the underside of the housing 64 and includes means for firmly clamping one end of a flexure 70. In the embodiment shown in FIGURE 5, the bail 22 includes a vertical member 74 aswell as a transverse piece 72 afiixed thereto. The vertical member 74 is adapted to clamp the flexure 70 at its upper end. The lower portion 28' of the vertical member is reduced for punch-clearance purposes and terminates in a stripper 30 arranged to engage recessed steps in the punches 10 and 11, substantially as described hereinabove. The transverse piece has provisions for clamping two groups of three flexures each symmetrically with respect to the vertical member. The latter flexures comprise .the limit guides 32 and 34 positioned opposite a pair of bail guides 76 and 78, and interposer flexures 40 and 42, each disposed between the facing guide surfaces of the aforesaid guides. As in the embodiment of FIGURE 2, the limit guides are arranged in two sets, each comprising a plurality of mutually spaced, aligned guides. Each bail guide preferably runs the width of the entire column of punches to present an unbroken surface to the oppositely positioned set of interposer flexures. The convex contour of the guide surfaces of the limit guides 32 and 34 is determined by the clamping angle on the transverse piece 72 and the dimensions of the stripper 30. The concave contours of the guide surfaces of the bail guides 76 and 78 are determined by the clamping angle on the transverse piece 72 and the width of the narrow lower portion of the vertical member 74. As before, the bail guide surfaces supply the necessary back-up action for the interposer flexures to enable the latter to transmit a force to the punches 40 and 42. As with relieved end 28' which introduces clearance notches in guiding surfaces 24,

26 of the embodiment in FIGURE 2, guides 76, 78 will be understood to be similarly relieved above each punch so as to clear the punch at non-punchingtimes. In FIGURE 5, both interposer flexures are shown in their punc position, i.e. in alignment with the punches 10 and 11.

The assembled actuator stripper mechanism is seen to be supported by mutually spaced, parallel flexure springs 80 and 82, preferably constituting a pair of springs at.

each end of the actuator. The springs 80 and 82 are clamped to a fixed support 86 as well as to the actuator:

to permit motion of the latter, in a vertical direction substantially normal to said springs.

FIGURE 5 further showsthe magnets 44 and 46 with windings 45 and 47 disposed thereon. As in the caseof the embodiment of FIGURE 2, the magnet pole faces are seen to be positioned behind the guide surfaces of the limit guides 32 and 34 respectively, i.e. out of contact with the interposer flexures if the latter make contact with the,

last-mentioned guide surfaces.

The operation of the embodiment of the invention illustrated in FIGURE 5 is substantially the same as that shown in FIGURES 2 and 4 and will be explained with reference to both embodiments. When rotary power is applied to the shaft in FIGURE 5, the eccentric coupling of the latter to the bushing 62 produces a reciprocating motion of the housing 64, as shown by the arrow. This motion is transmitted to the actuator by the flexure as a substantially linear reciprocating motion, the latter being permitted by, the fiexures and 82, .as explained herein- 4 above.

It will be noted from FIGURE 5, that the component parts of the actuator all reciprocate in the same manner,

in a vertical direction. This is also the case in the embodiment of the invention illustrated in FIGURES 2 and 4, in which the bail 22 and its associated stripper 30, the

limit guides 32 and 34, and the interposers40 and 42 are joined together to reciprocate in a vertical direction. In

both cases, only the magnets 42 and 46 remain stationary.

With the magnets 44 and 46 normally de-energized, the

normal position of the interposers 40 and 42,which alone consist of a magnetic material, will be the rest position. In this position, both interposers are in contact with the bail guide surfaces and hence in alignment with thecorresponding punches 10 and 11 respectively, as shown in FIGURE 5. Since the bail and the interposer reciprocate together, there is no friction between them andhence no Wear. In FIGURES 2 and 4, the interposer flexure 40 is shown in its normal position aligned with the punch 10 below. FIGURE 2 further shows the interposer flexure 42 in its actuated position which is obtained by energizing the magnet 44 upon the application of a signal to the terminals of the winding 45. The flexure 42 is then attracted to the pole faces 48 and 50 which, as illustrated in FIGURE 2, are stationed behind the guide surface 38 i and the aligned guide surface of the subsequent limit guide in the set. Consequently, the reciprocating flexure 42 is in flexibly conforming contact with the guide surface 38 which reciprocates therewith. The flexure 42 remains, however, out of contact With'the stationarypole faces 48 and 50 in order to prevent wear. In this position, the flexure 42 is seen to be out of alignment with the punch 11.

In FIGURE'2, the punches 10 and 11 are illustrated,

It will be appreciated that the movement of the interposer fiexures into or out of alignment with the punches cation of the actuator.

must be related in time to the reciprocating interposer motion transverse thereto. To this end, the selective energization of the magnets may be synchronized with the source of reciprocating motion. In the particular operating condition illustrated in FIGURE 2, the interposer 40 is about to contact the striking surface 13 and to drive the punch in a downward direction. The interposer flexure 42, being displaced beyond the striking surface 15 by the action of the magnet 44, will however miss the punch 11 which then remains in its normal position during the down-stroke of the actuator, being retained there, for instance, by conventional return spring means. During the up-stroke, the stripper 30 engages the step 18 of the punch 19 and returns the latter to its normal position. From FIGURES 2 and 3 it will be apparent that all the punches that were struck on the previous down-stroke are simultaneously returned to their normal position and that, furthermore, those punches which are to perforate the medium on a particular down-stroke will act in concert.

The movement which an interposer fiexure must execute to be in or out of alignment with its corresponding punch is relatively small. Accordingly, a punch unit which employs an actuator of the type disclosed herein, is capable of operating at high speed. Such high-speed operation is achieved without any sacrifice in the control of the punching operation, provided the selective energization of the magnets is properly synchronized with the recipro- The invention is simple in construction and relatively inexpensive to build. Owing to the fact that the contacting component parts all reciprocate together, the wear of these parts is minimized, while lubrication of the actuator is no longer required. Thus, far fewer breakdowns are experienced under sustained periods of operation and longer time intervals may elapse between periodic maintenance operations.

It will be apparent from the foregoing disclosure that the invention described and illustrated hereinabove, is subject to different modifications and variations. For example, permanent magnets may be employed in place of the normally de-energized magnets shown, with bucking coils adapted to selectively provide an opposing magnetic field when punching is desired. In this mode of operation, the normal position of the interposer flexures will be a position out of alignment with the punches. The flexures are allowed to assume their rest position in alignment with the punches only when the bucking coils are actuated. Any loss of energization current then results in a no-punch condition.

Under certain conditions, a simplification of the apparatus can be effected by holding the limit guides stationary, such as when the bail is also held stationary, provided only that appropriate means are provided to return the punches to their normal position in synchronism with the operation of the flexures. Such a modification will, however, result in increased wear of the component parts.

It will also be clear that the invention is not limited to the use of a serial punch unit employing a double column of punches and appropriate actuators, but is similarly applicable to a single column or, for that matter, a single punch. Nor is the invention limited to a punch unit, but it may find application wherever a driver element is selectively positioned to transmit motion to a driven element. As previously explained, the particular configuration of the source of reciprocating motion is immaterial.

From the foregoing disclosure of the present invention, it will be apparent that numerous modifications and departures, variations and substitutions will now occur to those skilled in the art, all of which fall within the scope contemplated by the invention.

What is claimed is:

1. A mechanical actuator comprising first and second mutually spaced limits each including a guide surface, a

bail symmetrically positioned between said limits and including a pair of guide surfaces each facing a limit guide surface and spaced therefrom, an elongated flexure of magnetic material located between each pair of mutually facing guide surfaces and having a rest position in flexibly conforming contact with a guide surface of said bail, magnet means adapted to operate through openings in said limit guide surfaces for selectively attracting said flexures into flexibly conforming contact therewith, means for reciprocating said flexures in a lengthwise direction jointly with said bail and said limits, and a pair of driven elements each positioned in alignment with one of said bail guide surfaces, each of said elements being adapted to have motion imparted thereto by one of said flexures when the latter is in its rest position and approaches one extreme of said reciprocation, said element remaining in its original position when said flexure is in contact with its corresponding limit guide surface.

2. A mechanical actuator comprising first and second guides including corresponding first and second mutually spaced surfaces respectively, an elongated leaf spring located therebetween and having a rest position in flexibly conforming contact with said first guide surface, means for selectively actuating said spring to assume a position in flexibly conforming contact with said second guide surface, means for reciprocating said spring in a lengthwise direction, and a driven element positioned in alignment with said spring only when the latter makes contact with said first guide surface and being adapted to have motion imparted thereto by said spring when the latter approaches one extreme of said reciprocation.

3. The apparatus of claim 2 wherein said leaf spring consists of magnetic material, said second guide surface including an opening, said spring actuating means comprising magnet means stationed behind said second guide surface and adapted to operate through said opening to attract said spring into contact with said second guide surface.

4. A mechanical actuator comprising first and second spaced guide surfaces, an elongated interposer positioned therebetween and normally in flexibly conforming contact with said first guide surface, means for selectively actuating said interposer to assume a position in flexibly conforming contact with said second guide surface, means for reciprocating said interposer in a lengthwise direction, and a driven element positioned to have motion imparted thereto by said interposer when the latter approaches one extreme of said reciprocation while in contact with one of said guide surfaces.

5. In a mechanical actuator, a driver element adapted to execute reciprocating motion in a first path, said driver element comprising a fiexure means having a stiff elongate axis along said first path and a stiff cross-sectional axis, said flexure means also being relatively non-frictional, being adapted to be normally flexed along a yielding axis orthogonal to said stiff axes, said flexure means fur ther being adapted to assume one of two flexed positions determined by a pair of limits and defining a second path along said yielding axis, substantially transverse to said elongate stiff axis and to said first path, said driver element being capable of transmitting motion to a driven element in only one of said two positions, and means for selectively moving said driver element to the second one of said two positions.

6. In a mechanical actuator, a driver element in the form of an elongated leaf spring adapted to execute lengthwise reciprocating motion, along an elongate axis thereof, said spring operating non-frictionally and having a cross-sectional yielding axis and, orthogonal thereto, a cross-sectional stiff axis; a pair of curved guide surfaces spaced from each other in a direction substantially normal to the direction of reciprocating motion, said driver element contacting a first one of said guide surfaces and flexible conforming thereto in its normal position, and means for selectively maintaining said driver element in the second one of said guide surfaces, said driver element being capable of transmitting motion to a driven element at one extreme of said reciprocating motion in only one of said two positions for flexing thereof along said crosssectional yielding axis.

7. A mechanical actuator comprising first and second guides including corresponding first and second mutually spaced surfaces respectively, an elongated flexure located therebetween and normally positioned in flexibly conforming contact with said first guide surface, said guides and flexure being joined at one end, means including spaced parallel leaf springs for supporting said joined components to permit linear motion thereof in a first direction substantially perpendicular to said springs, means for selectively moving the free end of said flexure in a direction substantially perpendicular to said first direction to cause said flexure to assume a position in flexibly conforming contact with said second guide surface, means for reciprocating said joined components in said first direction, and a driven element positioned in alignment with said flexure when the latter makes contact with one of said guide surfaces and adapted to have motion imparted conforming contact with said limit guide surface, means for reciprocating said flexure in a lengthwise direction jointly with said bail and said limit guide, and a punch positioned in alignment with said flexure when the latter is in its rest position, said punch being adapted tobe driven from its normal position by said aligned flexure when the latter approaches one extreme of said reciprocation, but remaining in said normal position when said flexure makes contact with said limit guide surface. I

9. In a card punch unit, a bail having a pair of concave contoured guide surfaces disposed in baek-to-back relationship and approaching each other in a downward direction, two sets of spaced, aligned, non-magnetic limit guides one being positioned to each side of said bail, each limit guide having a convex contoured surface facing one of said bail guide surfaces and identically spaced therefrom, a set of elongated, spaced interposer flexures of magnetic material positioned between each of said sets of limit guide surfaces and a bail surface, said interposer flexures being mutually spaced to overlap the space between successive pairs of aligned limit guides and having a rest position in flexibly conforming contact with a bail guide surface, magnet means stationed behind and between adjacent ones of said limit guides and adapted, through the space therebetween, to attract on oppositely positioned flexure into flexibly conforming contact with the surfaces of said limit guides, means for linearly reciprocating said flexures in a lengthwise direction joint- 1y with said bail and said limit guides, and a set of spaced .punches each aligned with one of said bail surfaces, each of said punches being adapted to be driven from a normal position by a flexure approaching one extreme of said reciprocation when said flexure is in contact with a bail guide surface, but remaining in said normal position when said flexure makes contact with the oppositely positioned pair of limit guide surfaces.

10. The apparatus of claim 9 wherein each of said magnet means comprises an electromagnet normally deenergized to maintain said interposer flexures in contact with said bail guide surfaces, and means synchronized with said reciprocation for selectively energizing said magnets.

11. The apparatus of claim 9 wherein each of said magnet means comprises a permanent magnet normally adapted to attract said interposer flexures into contact with said limit guide surfaces, and further comprising a bucking winding adapted to cancel out the field of said permanent magnet, and means synchronized wit-h said reciprocation for selectively energizing said bucking winding.

12. Apparatus for selectively actuating a mechanical element comprising bending guide means; an elongate flexible interposer positioned adjacent said guide means, said guide meansbeing adapted to so contact said interposer as to bend it flexingly along a prescribed driving path along which said interposer may drivingly actuate said element; and

means for displacing said interposer out of said path and out of said driving relation with said element. 13. In a mechanical actuator for imparting force to a prescribed driven element, a driver element adapted to assume one of two positions defined by limit means; only a driving one of said two positions permitting said driver,

element to transmit motion to said driven element, said limit means including a guide portion adjacent said driving position, being adapted to engage said driver element in a flexing, multipoint contact, thus rigidifying said driver element and'enhancing the force-transmitting properties thereof; and means for selectively moving said driver element to said driving position and into said multipoint engagement with said guide portion.

14. In an actuating arrangement including reciprocating driving means and driven means arranged to be reciprocatingly thrust along a prescribed drive path, the

combination therewith comprising:

elongate flexure means for selectively transmitting said thrust from said driving means to said driven means at a driving position thereof, said flexure means having an elongate axis relatively along said drive path and having a prescribed asymmetric cross-sectional stiffness, being relatively stiff along a first cross-sectional dimension and relatively resilient along a second cross-sectional dimension orthogonal to said first dimension; and positioning means adapted to selectively position said flexure means into a non-driving position by thrusting it along said second resilient dimension thereof relatively transverse said drive path for prescribed periods, after which said flexure means will assume said driving position along said path.

15. In an arrangement for applying force from a given driving member, oscillating along a prescribed driving path, to a prescribed driven member, spaced therefrom and adapted to be driven along a prescribed driven path, the combination therewith of force transmitting means disposed to selectively transmit force between said members, said transmitting means comprising:

non-frictional, constantly flexed flexure means; bending means joined to one end of said flexure means and normally engaging said flexure means along a substantial surface thereof so as to flex said flexure means disposing it along a prescribed transmitting path between said driving and driven paths for transmitting force therebetween; and translating means arranged to selectively displace the other end of said flexure means out of said transmitting path.

16. The combination as recited in claim 15 wherein said translating means comprises holding means adapted to normally hold said flexure means so displaced in a non-transmitting position, said holding means being selectively de-energized to allow said flexure means to return to said transmitting path at force transmitting times.

17. The combination as recited in claim 16 wherein said bending means comprises a straight beam secured to said fiexure means at said one end thereof and bent to thrusting path to assume a non-transmitting condiflex said flexure means along said transmitting path. tion, said fiexure means being bent fiexingly so as 18. An actuator arrangement comprising: thrusting means operating to non-frictionally apply to automatically return to said transmitting condition when released by said interrupting means and to enforce along a thrusting path; said thrusting means 5 gage said bending means so as to increase force-transcomprising a constantly flexed flexure means; refermitting capabilities along said thrusting path. ence frame means; driving means to provide relative movement between said flexure means and said References Cited by the Examiner frame means; bending means adapted to fix one UNITED STATES PATENTS end of said flexure means along said thrusting path 10 and also being adapted to flex the other end of said 2,831,355 4/ 1958 Z1mmerman.

flexure means sufiicient for bending thereof along 3,104,053 9/ 1953 Ra'bIIIOW 274119 X said thrusting path to assume a force transmitting 3,143,912 8/1954 Vogel et condition; and interrupting means for selectively displacing a portion of said flexure means out of said 15 WILLIAM S. LAWSON, Primary Examiner. 

1. A MECHANICAL ACTUATOR COMPRISING FIRST AND SECOND MUTUALLY SPACED LIMITS EACH INCLUDING A GUIDE SURFACE, A BAIL SYMMETRICALLY POSITIONED BETWEEN SAID LIMITS AND INCLUDING A PAIR OF GUIDE SURFACES EACH FACING A LIMIT GUIDE SURFACE AND SPACED THEREFROM, AN ELONGATED FLEXURE OF MAGNETIC MATERIAL LOCATED BETWEEN EACH PAIR OF MUTUALLY FACING GUIDE SURFACES AND HAVING A REST POSITION IN FLEXIBLY CONFORMING CONTACT WITH A GUIDE SURFACE OF SAID BAIL, MAGNET MEANS ADAPTED TO OPERATE THROUGH OPENINGS IN SAID LIMIT GUIDE SURFACES FOR SELECTIVELY ATTRACTING SAID FLEXURES INTO FLEXIBLY CONFORMING CONTACT THEREWITH, MEANS FOR RECIPROCATING SAID FLEXURES IN A LENGTHWISE DIRECTION JOINTLY WITH SAID BAIL AND SAID LIMITS, AND A PAIR OF DRIVEN ELEMENTS EACH POSITIONED IN ALIGNMENT WITH ONE OF SAID BAIL GUIDE SURFACES, EACH OF SAID ELEMENTS BEING ADAPTED TO HAVE MOTION IMPARTED THERETO BY ONE OF SAID FLEXURES WHEN THE LATTER IS IN ITS REST POSITION AND APPROACHES ONE EXTREME OF SAID RECIPROCATION, SAID ELEMENT REMAINING IN ITS ORIGINAL POSITION WHEN SAID FLEXURE IS IN CONTACT WITH ITS CORRESPONDING LIMIT GUIDE SURFACE. 